Launching today

Spellcast

Launching today

Desktop stage for coding agents: bubbles & Canvas

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Desktop stage for coding agents: bubbles & Canvas

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Productivity

Spellcast was built with GPT-6 Astra. I used Astra heavily to design and ship the desktop stage: passive bubbles for side thoughts, an editable Canvas for results, and completion notices when a turn ends. That burned through my Astra Pro 20x before launch day. Runtime target today: Codex on Windows (MCP + hooks). Local-first, open source, EN/中文 UI. The clip shows one host path; the core idea is the desktop stage around the agent.

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Launch tags:Productivity•Developer Tools•Artificial Intelligence

Launch Team / Built With

OpenAI

GPT-6 Astra Challenge

How did Astra change the scope or ambition of what you built?

Maker

Without Astra, Spellcast would have been a notification script. With Astra it became a real desktop product: a Rust core, a Tauri 2 shell with transparent always-on-top windows, an MCP bridge, and integrations for two agents (Codex and Grok Build). The decisive part was computer use. Astra didn't just write code — it launched the app, clicked through real windows, watched bubbles float up and completion cards appear, and fixed what it saw. That let me ship features I wouldn't have dared to test by hand: floating bubbles you can star and double-click onto the Canvas, an editable Canvas the agent writes into, and spoken completion notices. Astra turned "I wish my agent had a desktop" into something I could build alone in weeks.

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4h ago

Maker

📌

Hi Product Hunt 👋 I built Spellcast because agent sessions kept pulling me back to the terminal. I wanted the agent's side thoughts, its results, and "I'm done" to reach me where I'm actually looking — the desktop — without me babysitting a CLI. Three things it does: • Bubbles — the agent's asides float up while it works; star one to keep it, double-click to open it on the board. • Canvas — the agent writes results onto an editable Canvas as ideas (text, step sequences) that you can keep shaping. • Completion notices — a card plus a spoken alert the moment a turn ends, for both Codex and Grok Build. Honest note about the demo: Spellcast was designed around the Codex app/CLI, but my Codex Pro quota ran out right before the deadline, so the video shows the Grok Build integration instead. Everything you see is real and end-to-end, but the Codex-side flow (deep-linking a completion back into the exact session, replies from the Canvas) isn't on camera. I'd have loved to record it with Astra — its computer use is far ahead of what I could recreate with Cursor for driving the demo — but I was out of credits there too. Everything is open source. Happy to answer anything about the MCP setup, the hook-based completion notices, or the Canvas model.

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4h ago

OpenAI

GPT-6 Astra Challenge

How did Astra change the scope or ambition of what you built?

Maker

Report

4h ago

Maker

📌

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4h ago